File fit rings
 

All,
Been asking a bunch of questions here, and I appreciate the help. I'd like to get some file fit rings, but having a hard time finding some. The bore is 4.29 (.040 over 454) and the pistons need 5/64 rings. The top ring gap now is .024, and I think that could be closed up to .018 or so.

Regular replacement moly rings are about 55 a set, anyone know where to get file fit ones?

Thanks

IMO you're wasting your time worrying about the ring gap. You'll never notice .006". If you want to do something to make a good improvement, open the second ring gap up ~.005 more than the top ring.

Molly rings are becoming a thing of the past.

Ok, thanks. I haven't checked the 2nd ring yet, but say they are both .024 and I open the second one to .029, what will that do to make an improvement?

Also, the rings in the engine are probably fine (140 hours or so) but I have the engine apart for some upgrades. I figured a quick deglaze with the correct stone and re-ring. My question is if I were to use the same rings, what happens if the ring gap stagger got moved from its original spot, I assume the rings break in in their original spot and if moved will not seal as good, which was my main reason for a re-ring. Or am I just over thinking it?

BB,
You mean because people are using plasma?

I had a conversation with someone about 4-5 months ago and they basically said Moly rings were being phased out and going to be hard to get. I asked why? Was told everyone is using steel rings now. Steel rings are a much better ring and will take 10 times the beating a moly ring will. They do however require a different honing finish as with most different rings.

I think the steel rings are rough on the cylinder walls. I still use the moly rings in my engines think they work great. Total seal makes a bunch of them.

That's what all the auto manufacturers are using now.

if you had good ring seal before you took it apart no need to hone it,put it back and the rings will seal.make sure to lightly oil the bores&piston skirts.

No hijack Mr. M...................just thought I'd post this and see what others are doing

Your over thinking it. The rings move as engine is running. The ring gap does not stay in original spot that you put it. Reason for putting stagger on the different openings is so that you don't have a direct path (openings over each other) into the crank case.

My opinion.

Couple things here...
Ring gaps don't stay oriented in any way shape or form. The cross hatch angle in the cylinder will promote ring rotation...if done properly.
Opening up the second ring; this has been done for decades, now, and it helps prevent pressure form building between the first and second ring. Every cylinder has blow by and if enough pressure is allowed to build between the top two rings, the top ring will lift off the land in the piston and lose it's seal. Compression rings have to seal in two places...they have to seal against the cylinder wall, and they have to seal against the ring land in the piston or they won't hold compression (cylinder pressure).
Moly rings; it's my understanding, through talk in the industry, that no one is manufacturing moly rings any more. What's out there is all there is. With the advent of the OEM's going to narrower rings and going to steel, the after market just can't support the manufacturing cost of a Moly ring and it;s costing ring mfgrs more to make a Moly ring than they can sell it for. Steel rings are no harder on a cylinder than anything else. Look at the Cup teams that run a .9mm (.035") steel ring for 500 mi @ 9000 rpm (and honestly I believe they're closer to .7mm these days). These rings have coatings on them that are harder than diamonds and both the rings and cylinders, after inspection, show zero wear. The down side to this for the enthusiast is, while a Moly ring will seal on just about any cylinder finish, steel rings will require a lot more attention to detail for the machinist and he needs to have his game on when finishing for steel rings. ONe place where technology has improved is ring flatness, where a typical .043" MOly ring will have a flatness tolerance of +/- .0005, but if you look at that, it means there is a total flatness variation of .001" and when we're depending on that surface to seal against the land in the piston, that's not very flat. Newer ring technology is calling for flatness in the .00015" range and that provides a lot better sealing just from the ring standpoint alone. We can also look at reciprocating mass...on a 4.50 bore, the difference between a traditional 1/16" ring, and a .043" ring is 6 grams! Double that for both rings and you just reduced your recip. weight by 12g just by going to a slightly narrower ring. That may not seem like much, but try and take 12g off a piston or rod some time and see just how much material that is. It's a significant amount and will do nothing but contribute to longevity and reliability.

Thanks for the post, good read. I'll check the second ring gap and open it up if needed.

scott,i am not understanding your comment of + or -.0005 being .001.if i understand it correctly .0005 is the total amount of measured difference the ring can have,not from centerline of ring to face but i may be wrong.imo .001 is a lot.i totally agree that steel rings won,t hurt the bore with the coatings we have at our disposal today.

if you plan on reinstalling the used rings i would not change the gap now.jmo.

Flatness of +/- .0005 = total deviation of .001. Not face flatness, but flatness as when you lay the ring on a table. Most "performance" rings are ground flat but, for example, Total Seals AP (Advanced Profile) rings are lapped and can achieve a much flatter surface to seal on the ring land in the piston. I would venture to say a 5/64 iron ring isn't even ground, but parted on a lathe and left with a machine finish. This is why I told the OP don't worry about the gap...that ring is losing a lot of seal just in it's inherent design.

I understand the theory on opening up the second ring end gap. My question is what about the total seal gap less
Rings? Or do you not recommend using those style rings?

i used them in my boat engines and several others,so far so good but they are pricey. total seal ap rings are great and i used them in a buddy,s builds that have a ton of hours and still have a great seal.

I've used a few times and they had great leak down numbers years later.My ls motors are getting them.

The gapless rings are fairly inexpensive when you compare them to the other rings total seal offers.

I'd like to see a test with a blowby meter installed, with a properly setup gapped ring, vs a gapless..and see what is really going on. Conventional gapped rings aren't designed to seal sitting on engine stand with the engine off. I think its pretty much been proven many times by some pretty big time engine builders/race teams, that the low leakdown numbers when comparing gapless rings, have no real world relation to what is really going on once the engine is off the stand.

I recommend calling total seal. Talk to Keith if you can get him on the phone took me a week of calling multie times a day. Discuss your combination and get his recommendation.

The verdict has been in on gapless rings for years. They aren't used in the highest levels of racing.

when checking leak down on a fresh rebuild w/ file fit rings,I see 2% or less.Then on the other token,My engine ran like a mofo,some of the fastest speeds out of them.when leaked down,6 out of 8 cylinders had 40-50% leak down.go figure.

i agree,putting 100lbs air pressure in the plug hole will allow more air to leak through the ring gaps than when the piston is moving a mile per second in it,s bore.espically with the engine at operating temp.

It be cool to be able to hook up a blow by meter, and monitor those numbers, as when its time to do a freshen up. I read a post on one of the sites like yellowbullet or speedtalk, where they had a used/ran engine that had super low leakdown numbers with gapless rings, and when they strapped it to the dyno, the blowby cfm under full throttle load was off the chart.

Or like horseypower1 said, when the rings are up against the ring lands with pressure.

When people are talking gapless rings, can they state if gapless top or 2nd ring ? Thanks.

Top

H1, I just looked at the ring surface where they seal against the piston and there is a smooth cross hatch pattern to them like they were lapped. Just noting it.

The second ring is already .004 bigger at .029.

I have heard people running a gapless second ring, if they really sealed that well, wouldnt they cause problems on the first ring?
Thanks for the technical input rather than bickering(for every one not you)..

i want a blow by meter,where can i get one?

I asked for one for Christmas one year and got slapped :angry-smiley-038:

well if it was detonating/knocking it would have huge amount of blow by.also,were the rings actually broken in or did they just hammer it.
maybe the dry sump system wasn't plumbed right,who knows what was going on.

http://www.j-tecassociates.com/Engine%20inline2005.htm

http://www.labcell-automotive.com/au...strial/blow-by

http://www.jegs.com/p/B-B/B-B-Blow-B...50652/10002/-1

i looked at some blow by meters on line,they hooked one up to a stock engine and when they started it they said [IT BLEW THE BALLS RIGHT OFF OF IT].that is the one i want.

I thought it... you posted it.... LOL

in doing more blow by meter research i came across one that is made for sail boaters,it measures the wind that blows by the sails.who would of thunk?

They're a clever group, those blow boaters, they have plenty of time to think up ideas while whistling along at 10 mph.

yes,the few that i have met were strange!one in particular at west marine had quite the imagination.

Ran the top gapless rings before I hatted them motor used more oil than my standard gap ring pack, Just rebuilt 2 900sc mercruisers that also had the top gapless it used oil. I have herd lot of complaints about that before. If you ask me if the engine has no blow by the ring pack will fill up with oil and it will not preform well at all.

And the cylinder prep was done correctly!